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Kendall, Brown, Raymond tell Congress $194 billion budget request balances risks, quickens transformation
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By NASA
“We have a group photo of my first project here, ASTRO-H, and that one means a lot to me because I came [to that NASA project] fresh off the street. I was super scared and intimidated. It was me and three other [technicians], who were also all new, and a handful of very seasoned scientists and engineers. And we came together.
“And we actually came in — I believe — under budget, ahead of schedule, and exceeded all expectations for our test results. That’s kind of unheard of, you know what I mean? We had such a good environment in the lab. Everybody got along so well. It was all teamwork. And everything just gelled.
“So when I look back on that photo from 14 years ago, first of all, I look really young in it. And secondly, it makes me realize how blessed and lucky I’ve been to be here for so long. It reminds me of that guy who was really nervous and still did alright. [It reminds me] to have a little confidence in myself, just be me, and do the work. It’ll all work out.
“I love looking back at that first team photo and just remembering how raw everything was at the time and how well it still came out.”
—Clifton Brown, Engineering Technician, OMES III, NASA’s Goddard Space Flight Center
Image Credit: NASA/Thalia Patrinos
Interviewer: NASA/Thalia Patrinos
Check out some of our other Faces of NASA.
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By Space Force
The third annual 2024 Department of the Air Force Modeling and Simulation Summit was held at the Grand Hyatt River Walk in San Antonio, Texas, May 7-9.
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By NASA
This article is from the 2023 Technical Update.
The NESC Flight Mechanics Technical Discipline Team (TDT) provides support to all NASA Mission Directorates and throughout all mission phases. Highlights from this past year include three critical program support assessments, new discipline-advancing capabilities in simulation tools, and a preview of future efforts by the TDT to capture knowledge and expertise to pass on to the next generation.
Independent modeling and simulation (M&S) enables new insights into critical subsystem designs and offers opportunities for analyses to reduce risk acceptance for programs. Several ongoing assessments have contributed to improved flight certification processes and risk reduction. The Flight Mechanics TDT sponsored improvements to simulation tools that enabled new solutions to complex problems, and recent NESC Academy recordings captured the latest advancements in the discipline.
Notional risk scoring reduction through independent M&S
Modeling of crew seat acceleration during entry, decent and landing. The TDT supported the Commercial Crew Program by independently modeling and simulating commercial providers’ trajectory designs and on-board deorbit, entry, descent, and landing software. This past year, the team assessed the return of additional crew on commercial capsules for contingency scenarios and used independent simulation analyses to confirm this capability poses no significant changes in splashdown conditions, thus ensuring additional options for returning crew safely if the primary return vehicle is disabled. Additionally, the NESC is providing key assessments for manual control using a “paper pilot” based on actual pilot responses. This study enabled manual control as a viable survival scenario if the flight computer fails during deorbit, entry, descent, and landing phases of flight. These efforts contributed to an independent verification and validation of commercial providers’ designs that supported certification of commercial flights to and from the ISS.
Standing up a new independent M&S effort in support of the Mars Ascent Vehicle, a critical element delivering Martian soil and atmosphere samples for eventual return to Earth, provides value and increases confidence in the design of this key element for the Mars Sample Return Campaign. The Flight Mechanics team is contributing unique methodologies for studying the challenging dynamics of this two-stage solid motor design where the second stage is unguided and spin-stabilized.
Frame of Mars ascent vehicle second stage separation dynamics from an M&S animation Independent M&S of key staging and separation events for the SLS has resulted in affirmation of the SLS trajectory and guidance, navigation and control design. Flight Mechanics TDT members contributed analyses to evaluate the heliocentric disposal of the Interim Cyrogenic Propulsion Stage (ICPS).
Monte Carlo modeling of the Artemis 1
This past year, the TDT also completed an assessment that explored the interoperability between common mission analysis tools and enabled trajectory sharing between tools to solve more complex mission design problems (page 31). An NESC Technical Bulletin (page 47) and Innovative Technique (page 65) have been published on this topic.
NESC Academy recordings on trajectory optimization tools and frameworks, electric aircraft sizing methodologies, system optimization, and aerodynamic decelerator systems were important knowledge capture and transfer initiatives. These recordings are available to help train and educate engineers on the tools and processes NESC teams will use for future independent M&S efforts.
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By NASA
4 min read
NASA’s Hubble Finds that Aging Brown Dwarfs Grow Lonely
It takes two to tango, but in the case of brown dwarfs that were once paired as binary systems, that relationship doesn’t last for very long, according to a recent survey from NASA’s Hubble Space Telescope.
Brown dwarfs are interstellar objects larger than Jupiter but smaller than the lowest-mass stars. They are born like stars – out of a cloud of gas and dust that collapses – but do not have enough mass to sustain the fusion of hydrogen like a normal star.
This is an artist’s concept of a brown dwarf. This class of object is too large to be a planet (and did not form in the same way), but is too small to be a star because it cannot sustain nuclear fusion, since it is less massive than even the smallest stars. A brown dwarf is marked by wind-driven horizontal bands of thick clouds that may alternate with relatively cloud-free bands, giving the object a striped appearance. Whirling storm systems as big as terrestrial continents, or even small planets, might exist. The name “brown dwarf” is a misnomer because the object would typically appear red to the naked eye. It is brightest in infrared light. Many brown dwarfs have binary companions. But as they age, the binary system gravitationally falls apart, and each dwarf goes its separate way, according to a recent Hubble Space Telescope study.
The background stars in this illustration are a science visualization assembled from the Gaia spacecraft star catalog. The synthesized stars are accurate in terms of position, brightness, and color. Because this is not an image of the Milky Way, missing are glowing nebulae and dark dust clouds.
NASA, ESA, Joseph Olmsted (STScI) Astronomers using Hubble confirm that companions are extremely rare around the lowest-mass and coldest brown dwarfs. Hubble can detect binaries as close to each other as a 300-million-mile separation – the approximate separation between our Sun and the asteroid belt. But they didn’t find any binary pairs in a sample of brown dwarfs in the solar neighborhood. This implies that a binary pair of dwarfs is so weakly linked by gravity that they drift apart over a few hundred million years due to the pull of bypassing stars.
“Our survey confirms that widely separated companions are extremely rare among the lowest-mass and coldest isolated brown dwarfs, even though binary brown dwarfs are observed at younger ages. This suggests that such systems do not survive over time,” said lead author Clémence Fontanive of the Trottier Institute for Research on Exoplanets, Université de Montréal, Canada.
In a similar survey Fontanive conducted a couple of years ago, Hubble looked at extremely young brown dwarfs and some had binary companions, confirming that star-forming mechanisms do produce binary pairs among low-mass brown dwarfs. The lack of binary companions for older brown dwarfs suggests that some may have started out as binaries, but parted ways over time.
The new Hubble findings, published in The Monthly Notices of the Royal Astronomical Society, further support the theory that brown dwarfs are born the same way as stars, through the gravitational collapse of a cloud of molecular hydrogen. The difference being that they do not have enough mass to sustain nuclear fusion of hydrogen for generating energy, whereas stars do. More than half of the stars in our galaxy have a companion star that resulted from these formation processes, with more massive stars more commonly found in binary systems. “The motivation for the study was really to see how low in mass the trends seen among multiple stars systems hold up,” said Fontanive.
“Our Hubble survey offers direct evidence that these binaries that we observe when they’re young are unlikely to survive to old ages, they’re likely going to get disrupted. When they’re young, they’re part of a molecular cloud, and then as they age the cloud disperses. As that happens, things start moving around and stars pass by each other. Because brown dwarfs are so light, the gravitational hold tying wide binary pairs is very weak, and bypassing stars can easily tear these binaries apart,” said Fontanive.
The team selected a sample of brown dwarfs previously identified by NASA’s Wide-Field Infrared Survey Explorer. It sampled some of the coldest and lowest-mass old brown dwarfs in the solar neighborhood. These old brown dwarfs are so cool (a few hundred degrees warmer than Jupiter in most cases) that their atmospheres contain water vapor that condensed out.
To find the coolest companions, the team used two different near-infrared filters, one in which cold brown dwarfs are bright, and another covering specific wavelengths where they appear very faint due to water absorption in their atmospheres.
“This is the best observational evidence to date that brown dwarf pairs drift apart over time,” said Fontanive. “We could not have done this kind of survey and confirmed earlier models without Hubble’s sharp vision and sensitivity.”
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. Goddard also conducts mission operations with Lockheed Martin Space based in Denver, Colorado. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Learn More
NASA Telescopes See Weather Patterns in Brown Dwarf
Small Companion to Brown Dwarf
Media Contacts:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute, Baltimore, MD
Science Contact:
Clémence Fontanive
Trottier Institute for Research on Exoplanets at Université de Montréal
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Last Updated Mar 21, 2024 Editor Andrea Gianopoulos Related Terms
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